2,468 research outputs found

    First Law, Counterterms and Kerr-AdS_5 Black Holes

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    We apply the counterterm subtraction technique to calculate the action and other quantities for the Kerr--AdS black hole in five dimensions using two boundary metrics; the Einstein universe and rotating Einstein universe with arbitrary angular velocity. In both cases, the resulting thermodynamic quantities satisfy the first law of thermodynamics. We point out that the reason for the violation of the first law in previous calculations is that the rotating Einstein universe, used as a boundary metric, was rotating with an angular velocity that depends on the black hole rotation parameter. Using a new coordinate system with a boundary metric that has an arbitrary angular velocity, one can show that the resulting physical quantities satisfy the first law.Comment: 19 pages, 1 figur

    A Web-Based Interface For A High Performance Computing System

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    High performance computing systems (HPCS) target to execute software whether this software is a simple or complicated one. Most of HPCS should have an interface to enable software owners to upload their files to be installed by the HPCS administrator. The interface should be extensible to work together in the future with the other remaining parts of the complete system. Also it has to be divided into phases in order to make development easier and also to make those components reusable. It is the best option to make the software a platform independent one. To achieve that, J2EE (Java 2 Enterprise Edition) should be chosen to implement this interface and also free licensed and open source software have to be chosen such as Tomcat Jakarta server, MySQL to be used in the development phases. All of the previous recommendations are applied in this research prototype. On top of that, the interface prototype has been tested on local environment and has achieved the expected results. This report passes through all phases to have a proper web interface to be used for a HPCS

    Empirical Research on Realizing, Evaluating, and Validating a Conceptual Breast Cancer e-portal Model with Arabic Content

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    This paper presents an empirical research that realizes a previous research of a conceptual breast-cancer e-portal model with Arabic content. The paper starts with briefing the previous research, after that, it highlights the gaps need to be bridged and the problems need to be solved. A real development of an e-portal prototype is done for achieving the research goal. This e-portal prototype has applied the conceptual model of the previous research

    A framework for loosely coupled components to automate municipal services (FLCCAMS)

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    Unifying and computerizing the procedures of municipal operations and maintenance is of great importance to municipalities as well as to ministries of local governments. On top of that, enhancing municipal e-services in terms of efficiency, quality, reusability, distribution and interoperability of these services; is a goal for most of municipalities.  Municipalities need to unify and computerize the procedures of maintenance and operations for their assets. This will eliminate the difficulties to prioritize the maintenance tasks; to let every task takes its turn fairly. In addition, this will speed up performing such maintenance and operation tasks, and will decrease the bugs appear after the maintenance is done. Therefore, the objective of this research work is to define, design and evaluate a conceptual framework for loosely coupled components to automate municipal services as well as unifying and computerizing maintenance and operations in local governments. The scope of this research covers roads and public buildings as the most important parts of municipal assets

    By-Product Alcohol: Fusel Oil as an Alternative Fuel in Spark Ignition Engine

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    Fusel oil is a by-product obtained through the fermentation of some agricultural products. The fusel oil properties are closer to other alternative combustible types and the limited number of studies on the use of fusel oil as an alcohol derivative in SI engines constitutes to the base of this study. This paper experimentally examined the impacts of a by-product of alcohol, which is fusel oil by blending it with gasoline, on engine performance, combustion characteristics, and emissions in a 4-cylinder SI engine. The test was achieved at different engine speeds and a 60 % throttle valve (load). As results, brake power, BTE, and BSFC of F10 are higher at all engine speeds. Maximum engine BTE was 33.9%, at the lowest BSFC with F10. Moreover, it is worth seeing that the F10 under rich air-fuel ratio has less variation of COVIMEP compared to the F20 and gasoline. F10 represents shorter combustion duration, thereby, the engine power increased. NOx emission for F10 at 4500 rpm was lower than gasoline. The highest value of HC emission is obtained with F10 compared to gasoline and F20 with an average increase of 11% over the engine speed range. CO and CO2 emissions increased when using fusel oil blends

    Performance, Combustion Characteristics and Emission Tests of Single Cylinder Engine Running on Fusel Oil - Diesel Blended (F20) Fuel

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    Alcohols produced from a renewable source are amongst the important alternative fuels for internal combustion engines. Investigations on alternative fuels for compression ignition engines regarded as one of the major research areas. This paper details an experimental examination of the performance and emissions in single cylinder compression ignition engines operating with fusel oil F20 and pure diesel F0 at five engine speeds and 50% engine load. The test results indicated that the engine power and torque slightly decrease with the F20 at low speeds compared with pure diesel. Further, the in-cylinder pressure was decreased at all engine speed for F20 in comparison with pure diesel. The volumetric efficiency and fuel consumption were increased for F20 due the low heating value of fusel oil. The results showed that CO2 and CO emissions were increased because of the water content, low heating value and low cetane number for fusel oil. The maximum reduction in NOx emissions was 18% for F20 at 1500 rpm

    Prescribing patterns of gastrointestinal drugs in private clinics in Benghazi-Libya

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    Background: Prescription analysis can pinpoint areas of improvement in encounters issued by prescribing physicians. The present study was carried out to analyze prescribing trends for outpatients among consultants in the city of Benghazi-Libya.Methods: A total of 4000 prescriptions were collected from private pharmacies around the city of Benghazi, Libya. Indicators addressed included the patient's name, age, sex, and address, and the physician's name, address, and signature. The percentage of prescriptions lacking this information was calculated. Drugs prescribed by dosage, duration of treatment were also considered. The study focused on the commonly prescribed classes of gastrointestinal drugs and the most frequently prescribed drug of each common class. No attempt was made to evaluate the incidence of various gastrointestinal disorders. Results are expressed as frequency and percentage of prescribed medicines.Results: Information present in prescriptions and pertaining to the patient were name (2972, 74.3%), age (468, 11.7%), date of visit (107, 2.7%) while those for prescriber were name (1902, 47.6%) and signature (3612, 90.3%). None of the prescriptions contained sex of patient, his/her address, or registration number of the prescriber. All prescribed drugs were in brand names. Polypharmacy was not evident as all prescriptions contained 1-2 drugs.The number of prescriptions with a gastrointestinal drug(s) counted to 421 (10.5%) out of the total 4000 prescriptions. The most commonly prescribed classes of gastrointestinal drugs include in order, anti-hyperacidity, anti-emetics, anti-spasmodic, laxatives and anti-diarrheal with the most frequently prescribed drug of each therapeutic class being omeprazole (67, 48.9%), metoclopramide (57, 57%), hyoscine-N-butyl bromide (42, 55.3%), bisacodyl (44, 59.5%) and loperamide (30, 88.3%) respectively.Conclusions: The results of the present study indicate the need to improve prescribing among physicians, a task that can be achieved through inclusion of related topics such as prescription writing and rational drug use in undergraduate curricula and continuing medical educational programs

    Predicton of interface level height of stratified liquid-liquid flow using artficial neural network

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    In this study, artificial neural network (ANN) was used to predict the interface level height (ILH) of two immiscible liquids flowing in a horizontal pipe. A three-layer feed-forward back-propagation (FFBP) neural network was constructed and trained with experimental data of two different liquid-liquid flow systems reported in the literature. The all studied flow patterns were stratified flow (stratified smooth and stratified wavy with or without droplets at interface ). The input parameters of the ANN model were superficial velocity of phases, pipe diameter, the ratio of the lighter phase density to the heavier phase density (ρlp/ρhp) and the ratio of the lighter phase viscosity to the heavier phase viscosity (μlp/μhp), while the interface level height (ILH) of phases was its output. The Levenberg–Marquardt (LM) algorithm, the hyperbolic tangent sigmoid and the linear activation functions were used for training and developing the ANN. Optimal configuration of the ANN model was determined using minimizing the mean absolute percent error (MAPE) and mean square errors (MSE) between experimental and predicted ILH data by the ANN model. The results showed that the optimal configuration was a network with five neurons in hidden layer that was highly accurate in predicting the interface level. MAPE and correlation coefficient (R) between the experimental and predicted values were determined as 1.8% and 0.9962 for training, and 1.52% and 0.9996 for testing date sets, respectively

    Functional Analysis of the VirSR Phosphorelay from Clostridium perfringens

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    Toxin production in Clostridium perfringens is controlled by the VirSR two-component signal transduction system, which comprises the VirS sensor histidine kinase and the VirR response regulator. Other studies have concentrated on the elucidation of the genes controlled by this network; there is little information regarding the phosphorelay cascade that is the hallmark of such regulatory systems. In this study, we have examined each step in this cascade, beginning with autophosphorylation of VirS, followed by phosphotransfer from VirS to VirR. We also have studied the effects of gene dosage and phosphorylation in vivo. We have used random and site-directed mutagenesis to identify residues in VirS that are important for its function and have identified a region in the putative sensory domain of VirS that appeared to be essential for function. In vitro phosphorylation studies showed that VirSc, a truncated VirS protein that lacked the N-terminal sensory domain, was capable of autophosphorylation and could subsequently act as a phosphodonor for its cognate response regulator, VirR. Conserved residues of both VirS and VirR, including the D57 residue of VirR, were shown to be essential for this process. By use of Targetron technology, we were able to introduce a single copy of virR or virRD57N onto the chromosome of a virR mutant of C. perfringens. The results showed that in vivo, when virR was present in single copy, the production of wild-type levels of perfringolysin O was dependent on the presence of virS and an unaltered D57 residue in VirR. These results provide good evidence that phosphorylation is critical for VirR function
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